Megophrys lushuiensis, Shi & Li & Zhu & Jiang & Jiang & Wang, 2021

Shi, Shengchao, Li, Donghui, Zhu, Wenbo, Jiang, Wen, Jiang, Jianping & Wang, Bin, 2021, Description of a new toad of Megophrys Kuhl & Van Hasselt, 1822 (Amphibia Anura: Megophryidae) from western Yunnan Province, China, Zootaxa 4942 (3), pp. 351-381 : 360-371

Megophrys lushuiensis sp. nov.

Figs. 3–6 ; Tables 1, 3–5

Holotype. Adult male, CIBYN201909290 , collected from Gutan River in Luzhang Town , Lushui County, Nujiang Prefecture, Yunnan Province, China (25.977066° N, 98.795983° E, ca. 2358 m a.s.l.) by SC Shi, WB Zhu, and L Fu on 27 th September 2019.

Paratypes. One adult male ( CIBYN201909283 ), collected from Bashan , Luzhang Town , Lushui County (25.953588° N, 98.734431° E, 1986 m), other two toadlets ( CIBYN201909288–289 ) collected from Langbazhai Village , Luzhang Town (25.95118° N, 98.768903° E, 2006 m), by SC Shi, WB Zhu, and LFu on 27 th September, 2019 .

Other specimens checked. Five tadpoles. CIBYN201909119 , collected from Haobadi , Laowo Town , Lushui County (25.808908° N, 99.107779° E, 2363 m) on 23 rd September, 2019. Two tadpoles CIBYN201909171–172 , collected from Bashan , Luzhang Town , Lushui County on 27 th September 2019. CIBYN201909175 , collected from the same site together with the holotype. CIBYN201909176 , collected from a small stream near the Gutan River of Luzhang Town , Lushui County (25.958701° N, 98.717995° E, 2399 m) on 27 th September 2019. All tadpoles collected by SC Shi, WB Zhu, and L Fu .

Etymology. The species name lushuiensis is inferred from the type locality Lushui County, Yunnan Province, China.

Suggested vernacular name. Lushui horned toad (English), and Lu Shui Jiao Chan (aeḳfflffi, Chinese).

Diagnoses. Megophrys lushuiensis sp. nov. is assigned to the genus Megophrys sensu lato based on molecular phylogenetic analyses and the following morphological characters: canthus rostralis well-developed; a small horn’- like tubercle at edge of upper eyelid present; supratympanic fold distinct; axillary glands small, on sides of the breast; oral disc of tadpoles funnel-like; mouth of tadpoles lacking transverse rows of teeth; head length more than 25% of body size; upper jaw protruding beyond the margin of the lower jaw; no skin fold on back of head; maxillary teeth present; tympanum distinct; hind legs long and thin.

Megophrys lushuiensis sp. nov. is identified from its congeners by a combination of the following characters: moderate body size (SVL 31.0– 34.8 mm in males, n = 2); vomerine ridge weak, vomerine teeth absent; dorsal skin relatively smooth; tongue slightly notched behind; tympanum rounded and relatively large, 0.54 times of eye length; horn’-like tubercle on edge of upper eyelid small; tibio-tarsal articulation reaches middle eye, tibia relatively long, ca. 0.56 times of body length; finger tips rounded, not expanded to small pad; toes with narrow fringes and rudimentary webbing; ventral hindlimbs semitransparent purplish with greyish white pigments; ventral body scattered with distinct dark patches in the middle.

Holotype description. Figs. 3 and 4 ; Table 2. Measurements in mm. Body size small (SVL 34.8) and relatively robust; protruding beyond cloaca small, not visible from ventral view. Head moderate, longer than wide (HW 12.5, HL 12.8, IFE 6.2, IBE 9.6); snout rounded in dorsal view, slight projecting in profile, protruding beyond lower jaw; rostral appendage absent (SL 4.3); canthus rostralis distinct (right side wounded); loreal region concave; nostril oval, nearly oval, closer to eye than snout (SN 2.3, EN 2.1), distance between nostrils slightly larger than distance between upper eyelids (IN 4.1, IUE 3.9); tympanum slightly larger than half of eye diameter (EL 3.9, TYD 2.0), and larger than eye-tympanum distance (TYE 1.6); tympanum rounded, slightly raised above surrounding, upper edge conceal with supratympanic ridge; interorbital space flat, wider than upper eyelid (UEW 3.4); pineal ocellus not observed; vomerine ridges weak, vomerine teeth absent; maxillary teeth present; tongue weakly notched behind, medial lingual process absent.

Forelimbs. Forearm moderately long, slightly enlarged than upper arms, shorter than hand (FAL 6.7, HAL 7.6); fingers slender, without webbing and lateral fringes, subarticular tubercles present on finger I and II, absent on other fingers, base of first finger distinct larger than the second; inner and outer metacarpal tubercles slightly raised above hand, separated from each other; finger length formula II<I<IV<III; tip of fingers rounded, slightly larger than last phalanges, not expand to small pad (FIIIW 0.6, FIVW 0.6).

Hindlimbs thin and long, tibio-tarsal articulation reaches middle eye when leg stretched forward; thighs slightly shorter than shanks but longer than feet (TL 16.6, SHL 17.0, FOL 13.1, TFOL 21.1); toes long, relatively lengths I <II <V <III <IV, rudimentary webbed, webbing formula: I 2–2 ¾ II 2–3¾ III 3–4¼IV 4–3V, with narrow lateral fringes, tips rounded and not expanded; dermal ridges continuously present on ventral surface of toes; subarticular tubercles absent; outer metatarsal tubercle absent, inner metatarsal tubercle oval, small, positioned by the base of first toes (IMT 1.5).

Skin. Dorsal surface of head, body and limbs relatively smooth, scattered with small granular tubercles all over; tip of most granules with one keratinized spinule. Lateral head scattered with several granules below supratympanic ridges and around tympanum. A small tubercle present on outer edges of upper eyelids. Supratympanic ridges thin before and above departure with tympanum, expand into a drop–shaped of water after, and curve above tympanum. Two longitudinal skin folds present on dorsolateral body, extending from above posterior supratympanic ridges to middle body. A longitudinal “>-<” shaped skin ridge present on middle dorsum. Skin ridge on head between eyes absent. Four short near transverse skin ridges present on dorsal thighs and shanks. Several larger flat tubercles present on flanks with width of two or three finger tips. Ventral surface of body and limbs smooth. Pectoral glands flat, small, with the size of first fingertip. Femoral glands small, closer to cloaca than outer edge of knee. Spinous small granules present around cloaca.

Coloration in life. Fig. 3 . Dorsal surface basically saddle brown. A dark brown triangular pattern presents between eyes, edged with lighter color, posterior part of triangular pattern on head fused with blur “>-<” shaped dark brown pattern on dorsum. Dorsal limbs with several wide blur transverse brown bars. Lateral head brown; upper edge of supratympanic ridges light brown, while lower edge dark brown; tympanum and skin between tympanum to eye dark brown; a wide dark brown bar present under eyes on upper lips. Lateral body tan; tubercles on flanks lighter colored; groins dark orange. Ventral body lighter than dorsal. Gular and chest purplish grey, the longitudinal stripes extend from mouth corner to ventral upper arm and the central longitudinal stripe on throat are ambiguous; two small white patches present on lower lips below snout. Abdomen ivory, four or five large dark patches present on both sides of ventrolateral body; about a dozen of distinct black irregular patches present on middle belly. Skin on lower arm semitransparent purplish with greyish white pigments, inner forearms with two large black patches; skin on ventral hindlimbs semitransparent purplish with greyish white pigments. Ventral hand dim grey; inner and outer palm tubercles and dark orange; ventral surface of fingers stained with little dark orange, more distinct on finger I. Ventral feet dim grey, stained with dark orange. A black patch present around cloaca, not seem from ventral view. Pectoral and femoral glands cream white. Iris copper above, light grey below.

Coloration in preserve. Fig. 4 . Described when holotype fixed in formalin and then preserved in 75% ethanol for three months. Coloration lighter than in life, dorsal surface mostly grey, dark brown patterns on head, body and hindlimbs dim grey. Black patches on body and limbs remained black. Dark orange color on groin and ventral hand remained. Ventral surface whiter than in life. Purplish color faded.

Secondary sexual characters. In breeding male, nuptial pads present on inner dorsal surface of the first two fingers, tiny spines on the nuptial pads dense; single subgular vocal sac present in male.

Variation. Fig. 5 ; Table 2. Adult male paratype CIBYN201909283, with a smaller body size (SVL 31.0); deeper coloration; ventral hindlimbs covered with lesser greyish white pigments; ventrolateral side of belly with a large and long dark patch on both side; skin ridges on dorsolateral body connect with the “Λ” shaped skin ridge on middle dorsum. One of two toadlets collected with light brown dorsal coloration. Patterns on dorsum of two toadlets collected not distinguishable.

Tadpoles. Fig. 6 ; Table 3. Measurements in mm. Description based on the tadpole CIBYN201909171 ( Fig. 5 ) at Gosner stage 32. Body elongated, length 2.8 times of width (BL 12.1, BH3.9, BW4.4); head as wide as trunk; eyes moderate (ED 1.1), rounded, positioned on dorsolateral head, widely separated (PP 3.4); nares small, much closer to pupils than tip pf snout (NE 0.7, RN 2.5), internasal distance much shorter than interpupil distance (IND 2.4); oral disc funnel like, anterodorsal positioned, width 1.7 times of body width (ODW 7.6); submarginal papillae on lips in shape of short bar near the opening of mouth and oval near fringes, major axis of submarginal papillae pointing to the opening of mouth, four or five rows on middle lower lip, 3 rows of oval submarginal papillae on both sides of upper lips; keratodonts absent; spiracle in right-handed helix from ventral view, the spiracular tube not protruding beyond body wall, positioned 58% of the distance between tip of the snout and trunk-tail junction (SS 7.1), and below the horizontal mid trunk line; tail long, length 73% of total length (TAL 30.7); dorsal fin slowly arise above trunk-tail junction, maximum height 35% of body height (UF 1.4); ventral fin connected to the trunk, height subequal to dorsal fin, 33% of maximum body height (LF 1.3); maximum tail muscle height 94% of maximum body height, maximum tail muscle width 61% of maximum body width (TMW 2.7, TMH 3.6); anal siphon opens medially.

When alive, dorsal body and tail brown, without distinct patterns. lateral body light brown, skin on lower half body semitransparent, deep greyish; lateral tail light brown with dozens of small dark brown patches on tail; fins semitransparent. Ventral body semitransparent, scattered with silver tiny patches, deep grey intestines visible. A golden ring present around pupil, golden pigments scattered around the ring.

In preservation, coloration deeper; brown pigmentation on body more prominent than when alive; ventral body and tail fin semitransparent white with brown pigments; tiny silver patches on belly less distinct than when alive.

Comparisons. Megophrys lushuiensis sp. nov. is phylogenetically assigned to the subgenus Panophrys and can be distinguished from its congeners of the subgenus by morphological characters as shown in Table 5. We also compared the new species with other species of Megophrys .

By tympanum distinct large, Megophrys lushuiensis sp. nov. differs from species of subgenus Atympanophrys , i.e., M. gigantica , M. nankiangensis , M. shapingensis , and M. wawuensis (vs. absent, concealed or very small in the latter).

By maxillary teeth present, Megophrys lushuiensis sp. nov. differs from species of subgenus Ophryophryne , i.e., M. elfina , M. gerti , M. hansi , M. koui , M. microstoma , and M. synoria (vs. absent in the latter).

By head not wide flat and hind limbs long, Megophrys lushuiensis sp. nov. differs from M. carinense , M. chuannanensis , M. feae , M. intermedia , M. orientalis , M. popei , and M. platyparietus (vs. head wide flat and hind limbs short in the latter).

By lacking a single, wide and flat palpebral projection on the edge of the upper eyelid, Megophrys lushuiensis sp. nov. differs from species of subgenus Megophrys , i.e., M. lancip , M. montana , M. parallela , and most of species of subgenus Pelobatrachus , i.e., M. baluensis , M. edwardinae , M. kobayashii , M. ligayae , M. nasuta , and M. kalimantanensis (vs. present in the latter).

By lacking rostral appendage, Megophrys lushuiensis sp. nov. differs from M. stejnegeri (vs. having less rostral appendage in the latter).

By having a small horn-like tubercle at edge of upper eyelid, Megophrys lushuiensis sp. nov. differs from M. dringi (vs. very large in the latter).

By body size moderate, Megophrys lushuiensis sp. nov. differs from M. feii (two males SVL 31.0– 34.8 mm in the new species vs. four males SVL 24.5–25.1 in the latter). By finger tips not expanded, the new species differs from M. feii (vs. expanded in the latter).

For species from subgenus Xenophrys , by males’ body in moderate size (SVL 31.0– 34.8 mm, n = 2), Megophrys lushuiensis sp. nov. differs from species with larger males: M. aceras (55.8–62.4, n = 6), M. ancrae (39.1–45.3, n = 8), M. auralensis (76.7, n = 1), M. awuh (35.7–41.1, n = 4), M. damrei (47.7–57.1, n = 7), M. flavipunctata (56.9– 68.4 mm, n = 4), M. glandulosa (76.3–81.0, n = 10), M. himalayana (68.0–73.5, n = 6), M. lekaguli (55.6–66.6, n = 8), M. longipes (47, n = 1), M. major (71.6–87.5, n = 12), M. mangshanensis (62.5, n = 1), M. maosonensis (77, n = 1), M. medogensis (57.2–68.7, n = 21), M. megacephala (45.9–53.4, n = 12), M. monticola (38.4–49.5, n = 17), M. pachyproctus (35.3–35.7, n = 2), M. periosa (71.3–93.8, n = 12), M. robusta (73.5–83.1, n = 6), M. serchhipii (36.1–46.7, n = 25), M. shuichengensis (102.0–118.3, n = 7), and M. takensis (47.3–53.0, n = 3).

By males’ body in moderate size (SVL 31.0– 34.8 mm, n = 2), Megophrys lushuiensis sp. nov. differs from M. vegrandis (vs. 27.5–30.6, n = 4 in the latter).

By vomerine teeth absent, Megophrys lushuiensis sp. nov. differs from M. dzukou , M. numhbumaeng , M. oreocrypta , M. oropedion , M. pachyproctus , M. parva , M. zhangi , and M. zunhebotoensis (vs. present in latter).

For species in subgenus Panophrys , by males’ body in moderate size (SVL 31.0– 34.8 mm, n = 2), Megophrys lushuiensis sp. nov. differs from species with larger males: M. baolongensis (41.8–45.0, n = 5), M. baolongensis (41.8–45.0, n =5), M. binlingensis (45.1–51.0, n = 3), M. caobangensis (34.9–38.9, n = 11), M. caudoprocta (70.8–81.3, n = 4), M. chishuiensis (43.4–44.1, n = 3), M. daweimontis (34–37, n = 18), M. hoanglienensis (43.2 ± 2.2, n = 11), M. huangshanensis (36.0–41.6, n = 4), M. insularis (36.8–41.2, n = 5), M. jiangi (34.4–39.2, n = 9), M. jingdongensis (53.0–56.5, n = 3), M. jinggangensis (35.1–36.7, n = 2), M. liboensis (61.6–62.9, n = 4), M. mirabilis (55.8–61.4, n = 2), M. obesa (35.6, n = 1), M. omeimontis (56.0–59.5, n = 10), M. palpebralespinosa (36–38.9, n = 2), M. sangzhiensis (54.7, n = 1), M. spinata (47.2–54.4, n = 18), M. xiangnanensis (38.6–42.0, n = 11). By males larger (SVL 31.0– 34.8 mm, n = 2), Megophrys lushuiensis sp. nov. differs from smaller species: M. cheni (26.2– 29.5, n = 15), M. mufumontana (30.1–30.8, n = 2), M. rubrimera (26.7–30.5, n = 8), M. shimentaina (28.0–30.6, n = 12). By vomerine ridge present, Megophrys lushuiensis sp. nov. differs from M. binchuanensis , M. boettgeri , M. kuatunensis , M. leishanensis , M. lishuiensis , M. ombrophila , M. shunghuangensis , M. wuliangshanensis , and M. wushanensis (vs. absent in the latter). By vomerine teeth absent, Megophrys lushuiensis sp. nov. differs from M. dongguanensis , M. fansipanensis , M. jiulianensis , M. nankunensis , M. nanlingensis (vs. present in the latter). By tongue slightly notched behind, Megophrys lushuiensis sp. nov. differs from M. brachykolos , M. tuberogranulata , M. acuta , M. angka , M. lini , M. wugongensis , and M. yangmingensis (vs. not notched behind in the latter). By toes with rudimentary webbing, Megophrys lushuiensis sp. nov. differs from M. shuichengensis (vs. distinctly webbed in the latter). By tympanum about half size of eye and tibia longer than half of body length (TD/EL 0.54–0.54, TIB/ SVL 0.56–0.56, n = 2), Megophrys lushuiensis sp. nov. differs from M. minor (vs. tympanum distinctly large TD/EL 0.80–0.83 and tibia relatively shorter TIB/SVL 0.46–0.48, n = 4 in the latter).

There are twelve phylogenetically close species for the new species, of which nine species have nuclear gene data. Megophrys lushuiensis sp. nov. differs from M. daweimontis by relatively smaller male body size (SVL 31.0– 34.8 mm, n = 2 vs. 34–37 mm, n = 18 in the latter); vomerine teeth absent (vs. present), tibio-tarsal articulation reaching the middle eye when leg stretched forward (vs. reaching the tip of snout), and ventral hindlimbs semitransparent purplish with greyish white pigments (vs. reddish; Fig. 9G-L).The new species differs from M. spinata by a horn-like tubercle on edge of upper eyelid small (vs. absent), toes with narrow fringes and rudimentary webbing (vs. fringes and webbing well developed). The new species differs from M. sangzhiensis by eyes relatively smaller, TD/ EL 0.54, n = 2 (vs. eyes relatively larger TD/EL 0.62, n = 1), ventral hindlimbs semitransparent purplish with greyish white pigments (vs. ventral thigh and tibia orange red). The new species differs from M. binchuanensis by dorsal skin relatively smooth (vs. smooth), tubercle on edge of upper eyelid small (vs. absent), and lateral fringes on toes narrow (vs. wide). The new species differs from M. binlingensis by ventral hindlimbs semitransparent purplish with greyish white pigments (vs. ventral thigh and tibia dark orange red), and distinct patches scattered on middle ventral body present (vs. absent). The new species differs from M. palpebralespinosa by dorsal skin relatively smooth (vs. rough), horn’-like tubercle on edge of upper eyelid small (vs. slightly large), vomerine teeth absent (vs. present), tongue slightly notched behind (vs. not notched), and lateral fringes on toes narrow (vs. wide). The new species differs from M. omeimontis by vomerine ridge weak, vomerine teeth absent (vs. vomerine ridge strong, vomerine teeth present), and ventral hindlimbs semitransparent purplish with greyish white pigments (vs. ventral thigh and tibia orange red). The new species differs from M. jingdongensis by tympanum rounded (vs. oval), vomerine teeth absent (vs. present), and toes with narrow fringes and rudimentary webbing, webbing formula: I 2–2 ¾ II 2–3¾ III 3–4¼IV 4–3V (vs. fringes and webbing well developed, webbing formula: I 1–2 II 1–3 III 2–3½IV 3½–1½ V, Fig. 9A-F). The new species differs from M. wuliangshanensis by dorsal skin relatively smooth (vs. rough with dense granules), and lateral fringes on toes narrow (vs. absent); vomerine ridge weak (vs. absent).

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For three phylogenetically related species without nuclear gene data, the new species differs from M. caobangensis by distinct patches scattered on middle ventral body present (vs. absent), and skins on ventral thigh around cloaca with spinous small granules (vs. absent), tympanum relatively larger (TD/ED 0.54 vs. 0.40–0.50); differs from M. rubrimera by vomerine teeth absent (vs. present), toes with narrow fringes (vs. wide), and finger tips rounded (vs. finger tips slightly expanded and flattened to oval pads); differs from M. angka by lateral fringes on toes narrow (vs. absent), and tibia relatively longer (TIB/SVL 0.56, n = 2 in the new species vs. 0.47–0.50, n = 6 in the latter).

Distribution and Ecology. Megophrys lushuiensis sp. nov. is currently known from Lushui County, Yunnan Province, China. This species is found sitting on herbs’ leaves near mountain stream under broad leaf forests at elevations 1986–2399 m ( Fig. 7 ). Calls are rare during daytime of field work from 23 rd September to 27 th September 2019, when toadlets right after metamorphosis and tadpoles at Gosner stage 26 to 36 were collected. M. glandulosa was recorded at lower elevation (1213 m) in Luzhang Town, Lushui County, Yunnan Province, China. Tadpoles of the new species were found almost in every small stream investigated.

Figures

FIGURE 3. Photos of the holotype CIBYN201909290 of Megophrys lushuiensis sp. nov. in life. A, dorsal view. B, ventral view. C, lateral view. D, ventral view of hand. E, ventral view of foot. F, maxillary view, noting vomerine ridges weak and vomerine teeth absent.

FIGURE 4. Photos of the holotype specimen CIBYN201909290 of Megophrys lushuiensis sp. nov. A, dorsal view. B, ventral view. C, lateral view of head. D, ventral view of hand. E, ventral view of foot.

FIGURE 5. Color variation in Megophrys lushuiensis sp. nov. in life.A and B, dorsolateral and ventral view of adult male paratype CIBYN201909283, SVL 31.0 mm, respectively. C and D, dorsolateral view of two juveniles in situ, SVL 17.8‾18.7 mm.

FIGURE 6. Photos of the tadpole CIBYN201909171 of Megophrys lushuiensis sp. nov. in life.A, dorsal view. B, lateral view. C, ventral view. D, dorsal view of head.

FIGURE 7. Habitats of Megophrys lushuiensis sp. nov. in the type locality, Lushui County, Yunnan Province, China. A, landscape for forest. B, the stream under the forest.